Linux Kernel CVE-2025-68803

In the Linux kernel, the following vulnerability has been resolved:

NFSD: NFSv4 file creation neglects setting ACL

An NFSv4 client that sets an ACL with a named principal during file creation retrieves the ACL afterwards, and finds that it is only a default ACL (based on the mode bits) and not the ACL that was requested during file creation. This violates RFC 8881 section 6.4.1.3: "the ACL attribute is set as given".

The issue occurs in nfsd_create_setattr(), which calls nfsd_attrs_valid() to determine whether to call nfsd_setattr(). However, nfsd_attrs_valid() checks only for iattr changes and security labels, but not POSIX ACLs. When only an ACL is present, the function returns false, nfsd_setattr() is skipped, and the POSIX ACL is never applied to the inode.

Subsequently, when the client retrieves the ACL, the server finds no POSIX ACL on the inode and returns one generated from the file's mode bits rather than returning the originally-specified ACL.

The affected product is the mainline Linux kernel's NFSv4 server component (nfsd) across stable branches prior to the fix; exact vulnerable version ranges are not enumerated in the provided NVD data (no CPE strings were supplied), and the fix is distributed as multiple stable-tree commits (e.g. git.kernel.org commits 214b3964..., 381261f2..., 60dbdef2..., 75f91534..., 913f7cf7..., bf4e671c..., c182e1e0...). Distribution-packaged kernels are affected accordingly; Ubuntu has published fixed kernels via advisory USN-8096-1 (https://ubuntu.com/security/notices/USN-8096-1), and downstream tracking exists at VulDB (https://vuldb.com/?id.340678) and Siemens ProductCERT SSA-019113 (https://cert-portal.siemens.com/productcert/html/ssa-019113.html) for embedded/industrial products bundling the kernel. Only systems acting as NFSv4 servers with POSIX ACL support are practically exposed.